Arc welding apparatus



Feb. 7, 1939. so w 2,146,601

ARC WELDING APPARATUS Original Filed Oct. 23. 1936 Inventor-z Gareth G. SomerVille,

by 56 (ff H i gzttorneg.

UNITED STATES PATENT OFFICE 2,146,601 I ARC WELDING APPARATUS My invention relates to particularly to that type of the welding operation accordance with the consumption of an electrode 5 which is applied to the Gareth G. Somerville, Pi

ttsfield, Mass., assignor to General, Electric Company, a corporation of New York Original application October 23, 1936, Serial No.

107,185. 1937, Serial No. 143,31

arc welding and more arc welding in which proceeds automatically in work parallel to the line of welding with its end in arcing engagement with the work.

operating in view of operation proceeds automatically been started at the end of the elecing arc has welding is often For convenience, this type referred to as selffact that the welding once the weldthe trode and the electrode has been properly positioned along the line of welding.

When employing the self-operating process of welding, the welding current is supplied through the electrode. Heretof rent was supplied to paratively long length of possible to employ the ore unless the welding ourthe arc through a comprocess for welding seams of great length if a substantially uniform continuous weld was req uired. The welding electrode employed is usually provided with a-flux coating which not only within arcing distance serves to control the when fused a slag covering which protects the weld from the surrounding atmosphere and impositions the electrode of the work, but also welding arc and provides proves the quality of the deposited metal. When using a flux coated length the supply of trode generates suificient electrode of considerable current through the elecheat to disintegrate the flux coating and to interfere consequently with the successful performance of the self-operating process of welding.

I have discovered th at a uniform weld of great length may be made with the self-operating process of welding by positioning on the line of inner ends of which of one another and are connected to a s the work along welding two electrodes the adjacent are within arcing distance the outer ends of which ource' of welding current of sufiicient voltage to maintain two arcs in series with one another and then initiating the welding operation by adjacent inner ends of these electrodes.

triking an are between the This initiating arc with the consumption of the electrodes drops to the series connected arcs work and divides into two which move away from one another along the line of welding as the electrodes are con'sum ed. Due to the action of L produces at the point of 4 Claims. .(Cl. 219-8) the arcs upon the work no crater is formed in the work at the point of starting. Each arc directs molten weld metal toward the other and starting a uniform weld whichextends in each direction from the point of starting. It is apparent that by using two electrodes to form a single continuous weld in accordance with my discovery that the length of a continuous weld obtainable when using the self-operating'process of welding is twice that of the electrodes used and is obtained at twice the welding speed obtainable with heretofore proposed methods of welding with the self-operating process. By using a polyphase source of current which is connected to a plurality of electrodes which are simultaneously consumed by a plurality of pairs of series connected arcs, it is possible to obtain still greater speeds of welding. By resorting to particular electrode connections itis possible to obtain with a polyphase source of current welds of uniform quality the total length of which is the.combined lengths of the electrodes which are connected to the polyphase source of supply. e

The above-referred-to procedures of welding 5 by the self-operating process are disclosed and 2 claimed in my application Serial No. 107,185 for Arc welding, filed October 23, 1936, which also describes certain-apparatus by means of which these procedures are carried into effect. so

The subject matter claimed herein has been divided from this above-referred-to application and resides in the constructions illustrated in Figs. 1 and 2 taken from this above-referred-to application.

.In Figs. 1 and 2 of the grammatically illustrated a Welding machine capable of performing welding operations where the length of the weld is twice the length of coated electrodes l0 are supported with their bared end portions resting on electrode holders H which are ofis'et from the work l2 and slightly elevated above its surface. The fiux coated portionlof the electrodes is biased into arcing engagement with the work by plungers [3 which engage the electrodes at points between the electrode holders and the work. These plungers are forced into engagement with the electrodes through the agency of springs l4 reacting on drawing I have dia- 35 supports it which form a part of the frame structure of the welding machine. The electrode holders are formed of electrically conductive material and each is connected to a terminal it of a source of welding current which must be of suficient voltage to maintain two series connected. arcs with the desired now of welding current, The electrode holders ii are electrically insulated from the frame structure of the machine by insulating members ll positioned between these holders and the frame structure of the machine.

In Fig. 1 of the drawing the behavior of the welding arcs and the flow of weld metal has been indicated. It will be noted that no crater is formed at the point where the welding operation was initiated between the inner adjacent ends of the electrode. It will also be noted that the flux coating on each electrode forms a hood over the arc which directs the arc downward and to a great extent prevents the spatter of electrode material. A hood of the character illustrated is trio flux coating which is placed on the work with the thinner portion of the coating against the work. The same result may be obtained by the use of a flux coating next to the .work that is consumed at 'a greater rate than the flux co'ating located more remotely from the work. I

I have also discovered that it is possible to control the width of the weld and its penetration into the work by the use of cupreous bars having work enga ng portions of restricted section forming dams for the deposited metal on each side of the electrode and by the use of a grooved backing member having a work engaging surface of low heat conductivity. I

In Figs. 1 and 2 of the drawing the cupreous bars are shown at 18 and the grooved backing member at IS. The bars l8 are attached to supports 20 which also act as supports for the electrode holders i3. These bars have edged portions of restricted section which engage thework at opposite sides of-the electrodes and constitute dams for holding in place on the work the weld metal deposited from the electrodes and melted from the work. These bars also limit the activity of the arc in a lateral direction thus controlling 'its penetrating qualities. By controlling the distance the work engaging portions of these bars are spaced from one another, it is possible to obtain welds of desired width and penetration.

The action of these bars is assisted by the use located with its grooved portion 2i on the other side of the work below the welding electrodes.

formed by a copper bar 22 which is supported between the work engaging surface portions 23 of the bar. These work engaging surface portions are made of low heat conductivity by providing them with a plurality of grooves 26 which greatly limit the surface area of the backing member in engagement with the work. With this construction it is apparent that most of the heat must travel from the arc through'the work parts instead of passing from the work backing member. It is because of this restricted heat transfer to the backing member that the degree of penetration of the weld into the work isefiectively controlled.

The relative sizes of electrodes, work and lamping bars have been distorted in the drawing for purposes of illustrating the behavior of the welding arcs on the weld metal. I have found strips which are subsequently obtained by using an electrode having an eccenof the grooved backing member it which is The bottom of the grooved portion may be parts into the that the following spacings of the dams for as. ferent electrode sizes and plate thicknesses give the best results.

Plate Electrode Spacinz of thickness diameter dam e ges in inches in inches in inches it 3' Me Me 34 14 Ma Me new 940 i a it In order to prevent the formation of craters at the outer ends of the weld, strips of metal 25 may be attached at each end at the line of welding, and the welding operation interrupted after the welding arcs have traveled on to these broken from the work.

In view of the description of my invention above given it is apparent to I art that various modifications other than those illustrated may be employed without departing from the spirit and scope thereof and I consequently intend to cover in the appended claims all those modifications of my invention which fall within the true spirit and scope thereof.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for performing welding operations wherein the side of a welding electrode is applied to the work within arcing distance thereof and substantially parallel to the line of welding, comprising an electrically conductive electrode support, a source of supply connected to said support, and means between said support and the work for holding an electrode in electrically conductive engagement with said support and for biasing its arcing terminal portion into arcing engagement with the work.

, 2. Apparatus for performing welding operations wherein the side of a flux coated welding electrode is applied to the work substantially parallel to the line of welding, comprising an electrically conductive electrode holder laterally ofiset from the work and slightly elevated above the surface of the work, means between said elec-- trode holder and the work for holding the bared end portion of a flux coated electrode in electrically conductive engagement with said holder and for biasing the flux coated portion thereof into arcing engagement with the work, and

' means for supplying welding current to said elec- "the surface of the work, means between said electrode'holder and the work for holding the bared end portion of a'fiux coated electrode in electrically conductive engagement with said holder and for biasing the flux coated portion thereof into arcing engagement with the'work, means for controlling the width and degree of penetration of the weld, said means including cupreous bars having work engaging edge portions of restricted section forming dams for the deposited weld metal and a grooved backing member having a work engaging surface of low applied to the work substantiallyt those skilled in the heat conductivity, and means for holding the edge portions of said bars in engagement with one side of the work in spaced relationship to said electrode supported in said holder and for holding said backing member in engagement with the other side of the work with its grooved portion opposite the welding electrode.

4. Apparatus for controlling the width and degree of penetration of a weld formed by an arc welding operation comprising a plurality of cupreous bars having work engaging portions of restricted section forming dams for the deposited weld metal, a grooved backing member having a work engaging surface of low heat conductivity, means for holding said work engaging portions of said bars in engagement with one side of the work on opposite sides of the seam to be welded and in spaced relationship to one another, and means for holding said backing member in engagement with the other side of the workwith its grooved portion opposite said seam.

GARETH G. SOMERVILLE. 

